3357. Minimize the Maximum Adjacent Element Difference

Author: sergeyleschev

3001-3500/3357. Minimize the Maximum Adjacent Element Difference.ts

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+// Solution by Sergey Leschev
+// 3357. Minimize the Maximum Adjacent Element Difference
+// Binary Search
+
+function checkDifference(nums: number[], x: number, y: number, d: number): boolean {
+    let prev = 0
+    let count = 0
+
+    for (let i = 0; i < nums.length; ++i) {
+        if (nums[i] === -1) {
+            if (prev && Math.min(Math.abs(prev - x), Math.abs(prev - y)) > d) {
+                return false
+            }
+            count++
+        } else {
+            if (count) {
+                const diff = prev
+                    ? Math.min(Math.max(Math.abs(prev - x), Math.abs(nums[i] - x)), Math.max(Math.abs(prev - y), Math.abs(nums[i] - y)))
+                    : Math.min(Math.abs(nums[i] - x), Math.abs(nums[i] - y))
+
+                if (diff > d && (count === 1 || y - x > d)) {
+                    return false
+                }
+            }
+            prev = nums[i]
+            count = 0
+        }
+    }
+    return true
+}
+
+function minDifference(nums: number[]): number {
+    let maxGap = 0
+    let minVal = Number.MAX_SAFE_INTEGER
+    let maxVal = 0
+
+    for (let i = 0; i + 1 < nums.length; ++i) {
+        if (Math.min(nums[i], nums[i + 1]) === -1 && Math.max(nums[i], nums[i + 1]) !== -1) {
+            minVal = Math.min(minVal, Math.max(nums[i], nums[i + 1]))
+            maxVal = Math.max(maxVal, Math.max(nums[i], nums[i + 1]))
+        } else if (nums[i] !== -1 && nums[i + 1] !== -1) {
+            maxGap = Math.max(maxGap, Math.abs(nums[i] - nums[i + 1]))
+        }
+    }
+
+    let left = maxGap
+    let right = Math.ceil((maxVal - minVal + 1) / 2)
+
+    while (left < right) {
+        const d = Math.floor((left + right) / 2)
+        if (checkDifference(nums, minVal + d, maxVal - d, d)) {
+            right = d
+        } else {
+            left = d + 1
+        }
+    }
+
+    return left
+}